| abstract |
A highly effective fuel additive composition for control of intake valve deposits is described. It comprisesn (a) a gasoline-soluble Mannich reaction product of (i) a high molecular weight alkyl-substituted phenol wherein the alkyl group has a number average molecular weight of from about 600 to about 3000, (ii) amine, and (iii) aldehyde; and (b) a gasoline-soluble poly(oxyalkylene) compound having a viscosity in its undiluted state of at least about 70 cSt at 40°C and at least about 13 cSt at 100°C. These components are proportioned such that there are from about 0.2 to about 5 parts by weight of active Mannich base in (a) per part by weight of (b). |